RFR: 8365316: Remove unnecessary default arg value in gcVMOperations

[Albert Mingkun Yang]

Trivial removing effectively dead code.

Test: tier1

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Commit messages:
 - vm-op-remove-default-arg

Changes: https://git.openjdk.org/jdk/pull/26741/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=26741&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8365316
  Stats: 4 lines in 1 file changed: 0 ins; 0 del; 4 mod
  Patch: https://git.openjdk.org/jdk/pull/26741.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/26741/head:pull/26741

PR: https://git.openjdk.org/jdk/pull/26741